The following is known from the prior art: until now, so-called common-mode chokes which consist of two coils wound in opposition to one another and having a soft-magnetic core have been used in particular in supply lines in order to reduce electromagnetic interference. These chokes are generally introduced into the signal path to be filtered by means of soldering or welding.
One disadvantage with this consists in that a design of the circuit arrangement which has been selected once can no longer be optionally populated with such a filter, i.e. it is generally necessary to dispense with the filter in order to change the design of the circuit arrangement. If the circuit arrangements are supplier parts, the customer, as the consumer, cannot decide depending on requirements, whether the circuit arrangement is intended to be populated with a filter or not and is tied to the original design.
O-shaped cores which are pushed over sheet-metal lines, for example, are known. Nonetheless, these need to be sequentially processed and require a large number of individual process steps such as soldering or welding during production. If an effective pi filter which contains a combination of two capacitors and a coil is intended to be formed with such an arrangement, the manufacturing complexity is increased additionally by the application of the individual capacitors, with which contact needs to be made separately by means of welding, soldering, clamping or the like.
Against this background, the object of the invention consists in providing a filter device which can be introduced into electronic control devices using simple means and avoids the abovementioned disadvantages.